The anterior alveolus: its importance in limiting orthodontic treatment and its influence on the occurrence of iatrogenic sequelae.

Delineating the limits of orthodontic treatment in nongrowing individuals is important when making treatment decisions, especially in borderline orthodontic-surgical cases. The labial and lingual cortical plates at the level of the incisor apex may represent the anatomic limits of tooth movement. Cephalometric films of 107 adults were measured to determine the width of alveolar bone anterior and posterior to the incisor apex in each arch. Thin alveolar widths were found both labial and lingual to the mandibular incisors in groups of Class I, II, and III individuals with high SN-MP angle and in a group of Class III average SN-MP individuals. Thin alveolar widths were also found lingual to the maxillary incisors in a Class II high angle group. Clinical cases are presented showing that orthodontic tooth movement may be limited in patients with narrow alveolar bone widths and that these patients are likely to experience increased iatrogenic sequelae.